use crate::*;

fn min_of(values: Vec<i32>) -> Result<Outcome, FailedTo> {
    if values.is_empty() {
        return Err(FailedTo::ProcessInput);
    }
    Ok(Outcome::Scalar(i32::MIN)).and_then(|_| {
        values
            .iter()
            .min()
            .ok_or(FailedTo::FindMin)
            .map(|min| Outcome::Scalar(*min))
    })
}

impl Outcome {
    pub fn min(self) -> Result<Outcome, FailedTo> {
        match self {
            Outcome::Scalar(value) => Ok(Outcome::Scalar(value)),
            Outcome::List(values) => min_of(values),
        }
    }
}

#[cfg(test)]
mod unit_tests {
    use super::*;
    #[test]
    fn check_min() {
        let roll_result = Handful::grab(2, 20).roll();
        let min_result = roll_result.clone().min().unwrap();
        match roll_result {
            Outcome::List(values) => {
                let min = values.iter().min().unwrap();
                assert_eq!(min_result, Outcome::Scalar(*min));
            }
            _ => panic!("result is not a list"),
        }
    }
}